The present invention relates to fluid flow regulating apparatus in general, and more particularly to improvements in fluid flow regulators of the type disclosed in my U.S. Pat. Nos. 3,965,928 and 3,996,961.
U.S. Pat. No. 3,965,928 discloses a flow regulator for ducts wherein a shaft which extends transversely of the passage for the flow of a fluid medium carries a substantially V-shaped flap which is biased to open position by a helical spring whereby one section of the flap extends upstream of the shaft and the other section lies against a partition which is located in the plane of the shaft and divides the passage into two substantially mirror symmetrical channels. When the pressure of inflowing fluid increases, the fluid bears against one side of the one section and turns the flap against the opposition of the spring toward or all the way to the closed position. Such flow regulators exhibit several important advantages, especially as regards the sensitivity of the flap, i.e., its ability to move into a different position in response to minute changes of fluid pressure whereby the flap insures that the quantity of fluid that flows through the duct remains constant.
It has been found that the patented flow regulators operate highly satisfactorily when the fluid flows at a predictable rate. However, if the column of fluid which passes through the regulator housing vibrates, the flap is likely to flutter which results in short-lasting deviations from an optimum position and is likely to cause pronounced wear upon the bearings for the shaft. The shaft of the flow regulator which is disclosed in U.S. Pat. No. 3,965,928 is mounted in highly sensitive point bearing arrangements of the type resembling instrument pivot bearings. Such bearings are especially likely to undergo rapid and pronounced wear in response to flutter of the flap whereby the pointed tips of the shaft are likely to leave the sockets. Moreover, the utilization of highly sensitive bearings contributes significantly to the cost of the flow regulator.